A touch screen is an input device that allows a user to input commands of the user by selecting instruction contents on a screen of a graphic display or the like directly using a hand or an object. When the user touches a touch screen directly using the hand or the object, the touch screen detects touch points and drives the display according to instructions corresponding to selected icons, so as to implement specific displaying.
Touch screens currently commercially available include add-on type touch screens and integration type touch screens. The integration type touch screen is made by integrating a liquid crystal display panel with a touch panel when producing the liquid crystal display panel. The integration of the integration type touch screen has two fashions, one of which integrates a function of the touch panel on a color filter substrate of the liquid crystal display panel (which is also known as “on-cell integration”), and the other of which integrates the function of the touch panel between the color filter substrate of the liquid crystal display panel and an array substrate (which is also known as “in-cell integration”).
The “in-cell” integration can reduce a thickness of a liquid crystal display device significantly. At present, design patterns for the liquid crystal display device in the “in-cell” integration have multiple styles, one of which is a photo-sensing touch design. Nevertheless, such a touch design has a relatively low accuracy and can only sense light variation, and thus has a narrow applicable scope.
In another type of photo-sensing touch design, an integrated Touch Sensor (a touch sensing element) is added onto each pixel or several pixels. The integrated Touch Sensor is made up of two parts, i.e., Photo Sensor and LC Cap Sensor (Liquid crystal cell gap sensing element). This touch fashion makes touch more precise and sensitive. However, this touch fashion needs arranging a relatively large number of sensing elements, and has a significant influence on aperture ratio of the display device. Additionally, the LC Cap Sensor will increase a power consumption of the display device and tends to influence liquid crystal tilting, especially for the display device in an ADS mode.